Assessment of iron bioavailability in ten kinds of Chinese wheat flours using an in vitro digestion/Caco-2 cell model

Objective: To compare iron bioavailability (Fe BV) from ten selected kinds of Chinese wheat flours in order to provide scientific basis for further human trials and enable plant breeding programs to screen biofortified wheat cultivars.

Methods: An in vitro digestion/Caco-2 cell model was used to assess Fe BV of ten flour samples from six leading Chinese wheat cultivars and the stability of Fe BV in one cultivar was studied across three growing environments.

Results: Significant differences were observed in both Fe BV and Fe bioavailability per gram of food (Fe BVPG) among cultivars (P<0.01) grown at the same location with the same flour extraction rate. Zhongyou 9507 and Jingdong 8 had Fe BV 37%-54% and Fe BVPG 103%-154% higher than the reference control. In the Anyang environment, Zhongyou 9507 had a higher wheat flour-Fe level and Fe BVPG. Differences in Fe BV were detected in cultivars with different flour extraction rates.

Conclusion: Zhongyou 9507 and Jingdong 8 were identified as the most promising cultivars for further evaluation of efficacy by using human subjects. The growing environments had no effect on Fe BV, but did have a significant effect on Fe BVPG. Fe bioavailabilities in low-extraction (40%) flours were higher than those in high-extraction (78%) flours.